Apple's Mail app for iOS isn't a bad email client by any means. However, it just doesn't cut it for iPhone users that want a more intelligent and advanced email solution. If you're in the market for an app like that, Spark is absolutely your best bet.

We went through every free email app we could get our hands on in an attempt to find the best of the bunch. The App Store is full of email clients vying for your patronage, each with their own strengths and weaknesses. But Spark rises above the rest, mainly because its pros far outweigh its cons (and, spoiler alert, there aren't too many of those).

Intelligent Email Features

Let's get this out of the way — Spark is smart. The app's "Smart Inbox" seamlessly sorts your emails into one of three categories — "Personal," an inbox for emails from real people (mostly) who address you directly; "Notifications," emails typically from various sites and services you belong to; "Newsletters," a space for recurring emails like newsletters or advertisements.

What you find is most of the emails in "Notifications" and "Newsletters" can be ignored entirely, returning focus and control to your inbox. A typical email app will display all these emails together in chronological order, cluttering up your space and increasing the risk for the important stuff to get lost in the mix. Not with Spark.

If you want to send an email at a time you know you won't be by your iPhone, Spark lets you do just that. You can pick what day and time that email will be sent, so you don't have to worry about forgetting about it. You also won't forget to read or respond to important emails in your inbox thanks to "snooze," which reminds you of emails minutes, hours, or days after they are received.

The Best App Features

Spark sports virtually all the best features you look for in an email app. It allows for up to four swipe actions, which let you swipe left or right on an email to gain extra controls. You can select all emails when searching, which gives you much more control over the organization of your inbox, and the app automatically saves frequent searches, so you won't have to type the same search twice.

Speaking of searching, you can also search for attachments specifically, which makes it much easier to find that one Christmas photo your grandmother emailed you five years ago. When you draft up an email thanking her for that photo, you can minimize that draft to multitask in-app, so you never have to save and later fish it out of the draft folder.

In line with its intelligent email features, Spark sends you smart notifications as well. The app will only ping you when you receive an email to your "Personal" inbox, which makes for a much cleaner notifications view. In fact, you can even respond to emails from the lock screen, without ever jumping into the Spark app itself.

When you do need to open Spark, you don't need to settle for its default look. You can choose from four different color themes, handing a level of personalization and customizability to the user.

Built for iOS, Works Well with Others

Spark knows its platform. The app elegantly supports 3D Touch, which gives interacting with emails another layer of depth. Users can also protect their inbox with Touch ID, which will block anyone from accessing the app without your fingerprint. And, to the enthusiasm of iPhone X owners, Spark is "Notch-friendly," meaning the developers have optimized their app to fit the newest iPhone's unique display. It's the attention to detail that truly rounds out the entire Spark experience.

But it's not just in the way Spark works with the iPhone. Spark also works with other applications, and even includes native calendar support. When you connect your email to Spark, your information gets loaded into Spark's in-app calendar. You never need to leave the app to check your day's agenda.

You can also connect third-party applications to Spark — apps like Dropbox, Google Drive, Evernote, and more all work well with Spark, and serve to give users an abnormally complete mobile email experience.

In Conclusion ...

No matter how you shake it, Spark is the king of iOS email. It nails almost every note, with its intelligent suite of email and app features. Most of its competitors have some of these options, while other sport the rest. Spark virtually has them all, leaving very little to be desired.

If you're tired of the iOS Mail app and you're looking for a change, you cannot — and will not — go wrong with Spark.